THttpClient fails if you are using the standard .NET framework (i.e. not Silverlight), and you have generated your proxies using the async option. The error message is pretty unhelpful:
"No request has been sent"
This is caused by the BeginFlush method not being implemented outside Silverlight, which means that the request isn't sent.
I think two changes should be made:
- Either make BeginFlush / EndFlush abstract instead of virtual, or throw a NotSupportedException if the base implementation is called so that it's obvious what's going on.
- Remove the conditional preprocessor directives that exclude the implementations of BeginFlush / EndFlush.